Mercoid alarm and indicator



3 D. R. YARNALL MERCOID ALARM AND INDICATOR Filed June 12, 1928 m a 6 b. e. E. Z W m 2 Patented Nov. 24, 1931 UNITED STATES PATENT OFFICE ROBERT YARNALL, F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 YARNALL-WARIN G COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORA- 4 TION OF PENNSYLVANIA MERCOID ALARM AND INDICATOR Application filed June 12, 1928.

My invention relates to a boiler auxiliary indicator and alarm for operation during any abnormal heights of water in the boiler.

A purpose of my invention is to combine a Bourdon pressure tube adapted to operate anelectric signal circuit and a steam expansion chamber having a throttled, outlet with a high and low water steam discharge valve upon the water column'of a boiler, the valve being adapted to open into the expansion chamber under the action of any abnormal height of water in the column and to close I under the action of a normal height of water and the pressure tube being responsive to the pressure in the steam expansion chamber.

Afurther purpose is to combine a high and low water indicator with high and low water alarm mechanism that is adapted to be put temporarily out of operation by a boiler attendant after it has sounded an alarm and put out of operation without disturbing the continuing operation of theindicator throughout the duration of the high or low water. i

A further purpose is to combine a Bourdon pressure tube controlling a switch of an electric lighting circuit with an expansion chamber having a throttled discharge that does or does not sound an alarm. usually a whistle,

according to the position of a two-way valve.

I both sound an alarm and illuminate a light when the water height first becomes abnormal and then optionally stop the alarm without affecting the light by diverting a throttled discharge from the chamber away from the whistle without stoppingthe discharge, preferably sending the discharge to aheat exchanger such as a lowpressure heater, and may provide means by which the diverting valve automatically returns to its initial position as soon as the water height becomes normal so as to automatically send the throttled discharge again to the whistle whpn the water height again becomes abnorma Further purposes will appear in the specification and in the claims.

I have elected to show one form only of my invention indicating however minor modifications and selecting a form that is efficient Serial No. 284,841.

ber of a boiler, the device being adapted to operate by steam discharge from the water column chamber incident to either abnormally high or abnormally low water in the column. s

Figure 2 is an enlarged fragmentary vertical section through the steam expansion chamber at the outlet of the discharge valve from the water column chamber.

Figure 3 is a diagrammatic View showing the Bourdon tube connections and a desirable electric circuit controlled by the expansion and contraction of the tube.

Figure 4 is a section taken upon the line 41 of Figure 1, indicating a detail, shown however in a different position than that of Figure 1.

Like numerals refer to like parts in all figures.

Describing in illustration and not in limitation and referring to the drawings:

Inthe past it has been very usual to sound a whistle continuously throughout the periods of abnormal water height in the water column of a boiler, and this has meant that the whistle alarm has been sounding for considerable periods after the attendant has been made well aware of the abnormal condition and even after he has taken suitable corrective measures.

The first sound of the whistle has usually brought the abnormal condition to the proper attention of an operator who has promptly done whatever should be done to correct the condition, and the continuing blowing thereafter has been to a very considerable extent unnecessary and therefore has involved a mere needless noise usually heard far be yond the boiler room and that has frequently been a cause of uneasiness in the minds of many people within hearing outside of the boiler room.

A low water whistle is well recognized over an industrial plant as being indicative of a dangerous condition at the boilers and the unnecessary blowing of a low water whistle after the need for it has ceased, that c is after an operator has done whatever should be done to correct the abnormal condition, has frequently been a plant nuisance and one feature of my invention is directed to ward correcting this evil.

I combine a Whistle and a light in a way that results in simultaneously sounding the whistle and illuminating the light as soon as. thewater level begins to be abnormal and that permits an operator to stop the blowing of the whistle at any time after the abnormal condition has been brought to his attention without interfering with the light which remains illuminated as long as the' 12'wellabove the level of the surface'of the water in the boiler.

' The normal. water level is indicated at 13,

' midway between opposing upper and lower displacement weights 14 and 15 respectively.

The weights 14 and 15 operate against one another upon a valve member 16, the differencein the effective downward pull of the weieht members being used by any suitable connections, not shown, to control the position of the valve. I

Normally the lower weight is wholly submerged and the upper weight wholly above the surface of the water and the weia'ht members have such size and weight relations and such mechanical linkages to the valve 16 that the valve is then maintained closed. the effective downward pull of the lower wei ht- (wholly submerged) being then less than the downward-pull of the upper weight and the greater pull. of the upper weight being then used to hold the valve shut.

If the water in the oharnloer 10 becomes unduly-high the upper wei ght becomes wholly or. partially submerged and there is a resultant upward force of buoyancy upon the upper weight which makes the pull of the upper weightless than that'oi? the lower weight and the greater pull exerted by the lower weight then opens the valve.

In the same way if the water level becomes unduly low the lower weight becomes wholly or partially out of the water and the V resultant increase in the downward pull of the lower weight acts in the same direction as before, making the lower 'w'eight again effective to open the valve. 7 a

With normal water levels, the upper weight is predominant to an extent sufficient to hold the valve shut and with either abnormally high or abnormally lowwater a change in makes the lower weight predominate to an extent suflicient to'open the valve member.

The actual connections between the upper and lower displacement weights of the valve are not showmbeing irrelevant to thepresent invention. They may be in general in accord with mechanism disclosed in U. S. Patent 1,190,452 to D. W. Patterson dated July 11, 1916, for boiler alarm. a 1 1 The water column chamber 10 is illustrated as being provided 'witha water gauge 17 shown inclined in order to be more easily read froma position below the gauge near the boiler.

The valve 16 may be any valve adapted to open during an abnormal height of water in the boiler and to close when the height becomes again'no-rmal. Preferably it should open automatically whenever the water hecomes abnormally high, open automatically whenever the water becomes abnormally low, and shut automatically whenever the water level becomes normal. I

The water-control valve 16 discharges into an expansionchamber 18 which at 19 has a throttled discharge and at 20 makes connection to a Bourdon pressure tube21 so that the Bourdon tube expands and contracts responsively to the rise and fall of pressure inside the expansion chamber.

I connect the Bourdon tube to control the opening and closing of an electric circuit 22 that contains a light 23 orother indicator.

When the pressure in the expansion chamber rises, due to the opening of the valve 16, theBourdon tube expands and by suitable mechanism closes the indicating circuit at a suitable switch. I

I have shown the switch as comprising a container 24 of mercury. 25, the container being adaptedto rock about a pivot 26 so that in one position of the container,.that;in which the Bourdon tube. is under expansion, the.

mercury takes'up a position to make electrical connection between suitable contact members 27 'and 28 thereby completing the electrical circuit'22, and in another angular position of the container, that in which the Bourdon tube has contracted to its normal position, the mercury occupies a position away from the con.- tact members leaving an open circuit.

Obviously the Bourdon pressure tube may efi'ect the opening and'closing ofthe circuit inany suitable way and the mercury switch shown is intended for a conventional illustration of any switch adapted to beoperated by the expansion and contraction of the Bourdon tube. I The inlet end of the Bourdon tube isrigidly fastened at 29 to stationary case structure 30 and the outer end of thetube is connected by a link 31 to a rocker member32 whichis pivoted at 33 and is adapted to control the angular position of the mercury container-24.

a buoyant iorce upon one weight or the other The mercury container is mounted upon a Y rocker, member 34 and carries the contact members 27. and 28, which project inwardly from flexible electrical connections 35 .and 36 topositions such that when the container is tipped by the expansion of the Bourdon tube the mercury flows to and partially submerges the contact members.

When the Bourdon tube again contracts. due to closure of the valve 16, the rocker member 34 carrying the mercury container is returned to its original position, and the electrical circuit is opened by the mercury flow ing away from the contact members 27 and 28. v

It will be seen that the rockers 32 and 34 are operatively connected by a link 37 pivoted to the rocker 32 and spring pulled at 38 so as to engage one or other ofthe'sloping sur faces 39 or 40 of the rocker '34 according to I the extent of expansion of the Bourdon tube. In the first case the rocker 34 is resiliently pressed by the link 37 to its position for open circuit and in the other case it is pressed by the same link to its position for closed circuit. The two positions are determined by a suitable stop 41 and horns 42 and 43 from the rocker 34 on opposite. sides of the stop.

The flexible electrical connections 35 and 36 extend from suitable fixed terminals 44 and 45.

The circuit of the indicator preferably includes a light 23 at the boiler, desirably one or more lights 23 at any desired distant point as at a. board 46 for simultaneous display of the operation of a number of different boilers, and also may include an energizing coil for an electric magnet 47.

I find it desirable to make the alarm adapt ed to be cut out of operation after it has once i sounded the alarm and. may do this by giving the steam escaping through the throttled outlet 19 alternative paths, toa whistle 43 or to a. low pressure discharge pipe 49 and show a suitable two-way valve 50 for sending the steam discharge either to the alarm (whistle) or to the low pressure discharge pipe which preferably should connect into a heat exchanger, as for example into a low pressure heater.

Optionally the discharge from the pipe 49 may be to atmosphere. 7

From the expansion chamber the steam escapes through the throttle orifice 19, along a pipe 51 to the two-way valve 50 which delivers it to the whistle 48 when an operating handle 52 of the valve is in low position or to the discharge pipe 49 when the handle in raised position. Any suitable type of two-way valve may be used and the actual structure of this valve is therefore not shown.

The operating handle of the two-Way valve is shown weighted to make the handle nor- F mally occupy a position to send the discharglng steam to the whistle, the arm being vertically down and the weight being vertically below the valve stem when the valve is in position to direct the steam to the whistle, and the weighted arm being horizontal, as in Figure 4, when the two-way valve is in position to direct the flow to the low pressure discharge pipe 49.

Then weight and arm are down the discharge is through the whistle and when the arm is swung out to a horizontal position, as in Figure 4, the escaping steam is diverted to the low pressure pipe 49.

l have provided a latch member 54 that cooperates with the electric magnet 47 and an abutment 55 upon the valve stem to hold the weighted arm 52 up in horizontal position if it is raised into horizontal position dur ing the closure of the electric circuit 22 and adapted to automatically release the wei hted arm when the electric circuit fails, which it does whenever the water level becomes normal causing the pressure in the expansion chamber to fall to zero.

The abutment 55 is presented by the boss of the handle 52 and is adapted to be engaged b one end'of a rocker member 56 when this rocker member is being suitably deflected by the electro magnet 47 energized by the indicator. circuit 22.

As long as the magnet is energized the weighted arm of the two-way valve it raised will be held in raised position by the rocker member latching against the abutment and when the magnet loses its energy the latch member swings free and permits the weighted arm of the two-way valve to swing down and connect the whistle with the expansion chamber.

In operation, whenever the water level becomes abnormal, either abnormally high or abnormally low, the valve 16 opens.

The resultant pressure in the expansion chamber 18 simultaneously operates the alarm whistle 41 and expands the Bourdon tube to close the electric circuit 22, which is shown as including a light 23 at the boiler, a light 23 at any desired distant point or display board 46 at which it is desired to disclose the operation of the boiler, and the coil of the magnet 47. v

The energization oi the magnet 47 deflects the rocker member 56 to a position at which it is adaptedto latch back of the abutment on the boss of the weighted handle 53 of the two-way valve 50 if the handle is aised from its normal downward position at which the valve is sending the escaping steam to the whistle to a horizontal position at which it would divert the steam from the whistle to the low pressure discharge pipe 49.

The sounding of the whistle 48 at once calls the attention of the boiler operator to a need for making a correctin adjustment in the uantitv of water oin to the boiler.

needed adjustment and then stop the Whistle by raising the weighted arm 53 to its horizontal position, after which the latch mem-' ber maintains the weighted arm in raised position as long as the circuit 22 is closed, during which period the lights 23 and 23" are giving a continuous and silent indication that the water level is still abnormal.

lllhen the water level gets back to normal the valve 16 closes, the pressure in the expansion chamber falls to Zero, the Bourdon tube contracts breaking the circuit 22, the lights 23 and 23 go out and the magnet 47 loses its energy. Theiailure of the magnetism causes the rocker member 49 to release the abutment 55 and the Weighted arm 52 of the two-way valve then" swings down and connects the whistle again to the expansion chamber.

The operator observes by the 'oing out of the light that water level conditions are again normal, and if they again become abnormal his vigilant attention will again beawakened by the whistle, which, as before need not continue to blow after he has made a new and proper adjustment.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore claim all such in so far as they fall within the reasonable spirit and scope of my invention.

Having thus described my invention, whatv I claim as new and desire to secure by Let ters Patent is:

1. In apparatus for use with a boiler, 21

Water and steam compartment having water and steam spaces respectively adapted to be connected to the ater and steam spaces of a boilt f, a steam expansion chamber, a conduit connection between the chamber and the steam space of the compartment, a valve in the connection adapted to open and close respectively by abnormal and normal heights of water in the compartment, a Bourdon pressure tube connected to expand and contract responsively to increasing and diminishing pressure in the expansion chamber, an electric circuit controlled by the operation of the Bourdon tube, an indicator controlled by the operation of the circuit, a whistle, a low pressure heater and a valved means for discharging from the expansion chamber alternatively to the whistle or tothe heater.

2. In apparatus for use with a boiler, a water and'steam compartment having water and steam spaces respectively adapted to be connected to the water and steam spaces of a boiler, a steam expansion chamber, a conduit connection between the chamber and the steam space of the compartment, a valve in the connection adapted to open and close respectively by abnormal and normal heights of water in the compartment, a Bourdon pressure tube connected to expand and contract responsively to increasing and dimin; ishing pressure in the expansion chamber, an electric circuit controlled by the operation of the Bourdon tube, an indicator controlled by the operation of the circuit, a pipe from the expansion chamber, a two-way valve at the discharge end thereof having alternative first and second outlets according to correspondingly different settings of the valve, a whis tle connected to the first outlet, means adapted to automatically retract the valve to a position for discharge through the first outlet, a'latch adapted to hold the valve in po sition for discharge to the secondoutlet and a release for the latch operated by the breaking of the circuit.

DAVID'VROBERT YARNALL. 

